Simply composed electrochemiluminescence immunosensor based-on nano-scale BODIPY organic emitter for hypersensitive PSA detection

As electrochemiluminescence (ECL) sensors used for disease prescreening are usually subjected to various complex chemical modifications, we proposed a hypersensitive immunosensor using a dipyrromethene boron difluoride (BODIPY) derivative with a simple composition as the luminophore and a bistable iron(II) complex as the quencher. We determined that the metal-free BODIPY can achieve excellent photostability and easy lumi-nescence tuning via the introduction of different functional groups. A BODIPY derivative with a relatively simple chemical structure, 8-(4-bromophenyl)-4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (BPBF), was rationally selected as the ECL emitter. A bistable spin crossover iron(II) complex, [Fe(atrz)3]Cl2 (artz = 4-amino-1,2-4-triazole), an infrequent guest in the ECL field, provided the reaction platform and participated in the reaction with the co-reactant (S2O82-), which enhanced the sensitivity of the synthesized immunosensor. The immunosensor was designed for prostate-specific antigen (PSA) detection in the range of 0.001 pg/mL-200 ng/ mL, with a detection limit of 0.3 fg/mL (S/N = 3). Our strategy, based on small pure-organic luminophores and common transition metal complexes, will open up new possibilities for constructing simple ECL systems for hypersensitive detection of disease markers.